I would think that the mower blade would be too thick therefore putting more strain on your belts or clutch(whichever you have) and motor for the edger causing earlt wearout. At around $4 a blade...I wouldn't waste my time trying to fabricate into an edger blade.
I think Bedmeir was working on a design for this and other uses for old bent up mower blades. Check his posts out on that thread, might be a money making idea!! LOL<p>----------<br><a href="http://communities.msn.com/guidosequipmentpics/">"Guido"</a><br>David M. Famiglietti